Method of drilling



Sept 28, 1965 w. E. scARBoRoUGl-l 3,208,537

METHOD OF DRILLING Sept. 28, 1965 w. E. scARBoRoUGH 3,208,537

METHOD OF DRILLING 2 Sheets-Sheet 2 Filed Deo. 8, 1960 W////c7/77 Jcafofoay z2 INVENTOR.

f efr m .www g AroHA/fnr United States Patent O Texas Filed Dec. 8, 1960, Ser. No. 74,690 8 Claims. (Cl. 175-53) This invention relates to a method of producing boreholes and more particularly to a method of producing large boreholes in earth formations, and removing cuttings therefrom.

In the drilling of boreholes in earth formations, a drilling bit is secured to the lower end of a drill stem which is lowered and rotated to cause the bit to operate on the formation being encountered to cut or crush the same. A drilling fluid such as a liquid or gas is pumped downwardly through the drill stern and bit to cool and clean the bit, and to remove from the borehole the cuttings produced by the drilling operation.

The removal of the cuttings is not always efliciently performed, especially in the drilling of large diameter boreholes, because of the large amount of cuttings produced and the attendant reduction of the return velocity and lifting capacity of a given or limited volume of circulating fluid being pumped downwardly through a relatively small diameter drill stem, and returning upwardly through a much larger annulus area between the drill stem and the Wall of the hole being drilled.

It is an object of this invention to provide a new and improved method of producing and enlarging boreholes in earth formations.

Another object is to provide a new and improved circulating method for removing formation cuttings from a borehole.

Another object is to provide a new and improved fluid circulating system for removing cuttings through a relatively small borehole separate from another borehole which is being enlarged.

Another object is to provide an improved method of producing large boreholes in earth formations, useful for mine and Ventilating shafts, missile silos, construction work, underground storage and the like.

Other objects will become apparent from the following description and accompanying drawings, in which:

' FIG. 1 is a diagrammatic view of a drilling rig with attendant components, and a vertical cross section through an earth formation, illustrating the new and improved drilling method.

FIG. 2 is a diagrammatic representation of a vertical cross section of earth formation showing two boreholes which intersect to establish communication therebetween.

FIG. 3 is a detail view of an ejector pump used in the drilling fluid circulating system.

FIG. 4 is a detail view of a modified form of lift pump.

Referring to FIG. 1, a drilling rig is shown generally at 1 having a drawworks 2, a rotary table 3, a drive kelly 4, a swivel 5 and fluid lines 6 and 6. A fluid pump is shown at 7 which supplies drilling fluid under pressure through the fluid line 6 and swivel 5 downwardly through the kelly 4 and drill `stem 8 and drilling bit 9.

As shown diagrammatically in FIG. 2, a first borehole may be produced by drilling in a conventional manner. The borehole 10 is substantially vertical and extends preferably downwardly substantially below the point to which this borehole will later be enlarged. A second borehole 11 is spaced from the borehole 10 and may be drilled with the same or another rig. The borehole 11 may be drilled obliquely, or directionally, so that it will intersect the first borehole 10 near its nether portion.

Alternatively, the borehole 11 may be drilled downwardly to a position near the lower portion of borehole ICC 10, and communication established between the lower portions of boreholes 10 and 11 by side wall drilling, perforation, or fracturing the formation between the boreholes by introducing hydraulic or other pressure into borehole 11.

Referring again to FIG. 1, the borehole 10 may, for example, be drilled with a 12% diameter bit in the usual manner to a depth of approximately 1200 feet. The second borehole 11, for example, may also be drilled with a 121A diameter bit in a direction so as to intersect the first borehole 10 at approximately the 1000 foot level. The drilling bit 9 which may be from 30 to 72" in diameter is then secured to the drill stem 8 in order to enlarge the borehole 10 to the desired diameter, as at 24, to a depth which may be 900 feet, for example. The drill bit 9 is rotated by the rotary table 3 driving the kelly 4 and the drill stem 8. As the borehole 10 is being enlarged to the desired depth by the drill bit 9, the cuttings produced by such enlargement may pass downwardly into the first borehole 10 and upwardly through borehole 11 which boreholes are much smaller in diameter than the enlarged bore 24. Within the second borehole 11 there is provided an ejector pump 12 which is supplied through fluid line 6 with drilling fluid from the fluid pump 7. The formation cuttings and drilling fluid are circulated downwardly in borehole 10 and upwardly through borehole 11 through the conductor pipe 13 and shale shaker 14 into the mud pit 15, whereupon the fluid may be picked up by pump 7 an recirculated through the fluid lines 6 and 6 to the borehole 10 and to the fluid ejector pump 12 respectively. The ejector pump 12 serves to accelerate the upward movement of the circulating fluid in borehole 11 by reducing the pressure of the fluid in borehole 11. The pump 12 may be placed at a depth of from -500 feet, for example.

An air or gas compressor 16 is shown which may supply circulating lluid through the valve 17 and through the fluid lines 6 and 6 in the manner just described. If desired, a liquid may be circulated by the pump 7 through the fluid line 6 and downwardly into borehole 10 and upwardly through the borehole 11 while the compressor 16 is supplying air or gas through fluid line 6' to the ejector pump 12 to aerate the liquid, thus enhancing its upward movement out of the borehole 11.

A metal casing 18 may be -secured in the borehole 11 to seal the same, and to alleviate erosion of the side walls of the borehole 11 by the action of the circulating fluid and cuttings passing therethrough.

Referring to FIG. 3, the ejector pump 12 is shown within casing 18 in borehole 11. The fluid line 6' may terminate in an upwardly directed nozzle 19, which discharges drilling fluid into a venturi member 20 to accelerate the upward circulation of the fluid. A plate 21 serves t-o position the nozzle 19 and venturi member 20, and a packing member 22 may be Isupplied, between the plate 21 and the wall of the casing 18. The fluid and cuttings being circulated from borehole 10 upwardly through borehole 11 may enter the pump 12 through the space 23.

A modified pump 28 is shown in FIG. 4, wherein drilling fluid is supplied through fluid line 6', and directed upwardly `through nozzle 19 to enhance the upward movement of circulating fluid and cuttings which pass through lopening 25 in positioning plate 26.

Referring to FIG. l, the drilling bit 9 may have an annular packing gland 27 fitting within the bore 24 so that the drilling fluid may not readily escape upwardly past the drilling bit 9.

As can be seen in FIGS. 1 and 2, the borehole 10 may extend downwardly a substantial distance below its intersection with borehole 11, thus providing a space where Patented Sept. 28, 1965A junk or other detritus may lodge without interfering with the drilling operations.

The invention is not limited to the embodiments shown. Various changes, within the scope of the following claims, will occur to those skilled in the art.

I claim:

1. A method of producing a large bore hole having its upper end open to the surface of the earth comprising producing a first borehole, drilling a second borehole spaced from said first borehole, connecting the said borehole near the nether portions thereof, enlarging the said first borehole from the surface of the earth to a substantial depth, circulating the cuttings produced by the said enlarging downwardly in the said rst borehole and upwardly through the said second borehole, and accelerating the cuttings upwardly through said second borehole.

2. A method of producing a large borehole open to the surface of the earth comprising drilling a first borehole, drilling a second borehole spaced from said first borehole, establishing communication between the said boreholes near the nether portions thereof, enlarging the said first borehole downwardly from the surface of the earth, circulating the cuttings produced by said enlarging downwardly in said first borehole and upwardly through said second borehole.

3. A method of producing a large borehole having its upper end open to the surface of the earth comprising producing a first borehole, drilling a second borehole spaced from said first borehole, connecting the said boreholes near the nether portions thereof, enlarging the said first borehole downwardly from the surface of the earth, circulating the cuttings produced by the said enlarging downwardly in the said first borehole and upwardly rthrough` the said second borehole, and pumping the cuttings upwardly through said second borehole.

4. A method of -producing a large borehole open to the surface of the earth comprising drilling a first borehole, drilling a second borehole spaced from said first borehole, establishing communication between the boreholes near the lower portions thereof, enlarging the said first borehole downwardly from theA Surface of the earth, circulating a liquid downwardly through said first borehole and upwardly through said second borehole, and simultaneously introducing an elastic pressure fluid in said second borehole.

5. A method of producing a large borehole open to the surface of the earth comprising boring a first hole,

boring a second hole obliquely to intersect the lower portion `of the said first hole, enlarging the said first hole downwardly from the surface of the earth, circulating a fluid downwardly in said first hole and upwardly in said second hole, and reducing the fluid pressure in a portion of said second hole.

6. A method of producing a large borehole in earth formations comprising boring a first hole, boring a second hole to intersect the lower portion of the said first hole, enlarging the said first hole downwardly from the surface of the earth, circulating a liquid downwardly in said first hole and upwardly in said second hole, and simultaneously aerating the liquid in said second hole.

7. A method of producing a large borehole in earth formations comprising boring a first hole, boring a second hole lto intersect the said first hole, enlarging the said first hole downwardly from the surface of the earth, circulating -a fluid downwardly in said first hole and upwardly in said second hole, and pumping the fluid upwardly from a position within said second hole.

8. A method of drilling earth formations comprising producing a rst borehole, drilling a second borehole vspaced from said first borehole, connecting the said boreholes near the nether portions thereof, enlarging the said first borehole downwardly from the surface of the earth, circulating fluid downwardly in the said first borehole and upwardly through the said second borehole, and simultaneously effecting a fluid pressure differential accelerating the circulation upwardly between said first and second boreholes.

References Cited by the Examiner UNITED STATES PATENTS 2,383,496 8/45 Nebolsine 175-62 2,823,900 2/58 Kandle 175-53 2,861,428 11/58' Hendrix 175-53 2,880,587 4/59 Hendrix et al. 6l-0.5 2,928,468 3/60 Wienands 175-53 2,930,586 3/60 Long 175-325 2,934,904 5/60 Hendrix 61-0.5

CHARLES E. OCONNELL, Primary Examiner.

BENJAMIN BENDETT, BENJAMIN HERSH,

Examiners. 

1. A METHOD OF PRODUCING A LARGE BORE HOLD HAVING ITS UPPER END OPEN TO THE SURFACE OF THE EARTH COMPRISING PRODUCING A FIRST BOREHOLE, DRILLING A SECOND BOREHOLE SPACED FROM SAID FIRST BORHOLE, CONNECTING THE SAID BOREHOLE NEAR THE NETHER PORTIONS THEREOF, ENLARGING THE SAID FIRST BOREHOLE FROM THE SURFACE OF THE EARTH TO A SUBSTANTIAL DEPTH, CIRCULATING THE CUTTINGS PRODUCED BY THE SAID ENLARGING DOWNWARDLY IN THE SAID FIRST BOREHOLE AND UPWARDLY THROUGH THE SAID SECOND BOREHOLE, AND ACCELERATING THE CUTTINGS UPWARDLY THROUGH SAID SECOND BOREHOLE. 